Architecture of minor salivary gland duct/lymphoid follicle associations and possible antigen-recognition sites in the monkey Macaca fascicularis.

In Macaca fascicularis, lymphoid follicles with germinal centres related to minor salivary gland ducts are frequently found in the mucosa of lips, cheeks and the soft palate. Three semi-three-dimensional reconstructions, each based on 3 sets of 230-300 serial Epon sections, of such duct/follicle-assemblies (2 in the soft palate and 1 in the lip) and electron microscopic observations were made. These revealed that (1) these structures were about 0.05-0.1 mm3 in size, (2) they were found preferentially at sites where small interlobular ducts fused to form a pelvis-like basin from which blind duct portions protruded into the surrounding lymphoid tissue and (3) they often included a germinal centre which partly embraced blind ducts. The walls of such blind ducts were heavily infiltrated by lymphocytes and in part blast-forming T-cells. Portions of the walls of interlobular and main secretory ducts, passing directly or peripherally through follicles, were also infiltrated with lymphocytes. The duct lumen within the follicles contained clusters of Gram-negative bacteria, probably rods. Based on these findings, it is argued that gland duct/follicle assemblies represent physiological entities, either formed and re-formed temporarily or of long-standing nature, which may provide the locus (i.e. tonsillar microcrypt-like pouches) and the structural matrix necessary for local antigen recognition. The antigens (bacteria, macromolecules in salivary fluid, etc.) might enter the above structure by way of the secretory ducts. Such matrices may also exist in man.